The cytoskeletal organization of the developing rat optic nerve will be studied by a variety of biochemical, immunological and morphological studies. We will study the differential appearance of the neurofilament proteins in the optic nerve, previously observed in our laboratory by biochemical means, with monospecific antibodies against each of the neurofilament polypeptides at the light and electron microscope level. We will also study the expression of vimentin and glial filament protein in the optic nerve throughout development in order to study the relationship between the two types of filaments. We will characterize internexin, an intermediate filament associated protein isolated in our laboratory, for its ability to bind intermediate filament and microtubule proteins, and study its possible function as an organization center for the cytoskeleton in development, and we will do the immunolocalization studies of monospecific antibodies made against this protein. We will also study the axonal transport of a number of these cytoskeletal proteins in development in order to give us a further understanding of the organization of the cytoskeleton during maturation and axon outgrowth. These studies are designed to give us insights into the construction of the cytoskeleton of both the neurons and glia during development. An understanding of these events can give us insights into the failure of adult neurons to regenerate after injury or disease.